Constant volume variable speed driven vane pump



J1me 1952 H. c. FRENCH 2,600,633

VCONSTANT VOLUME VARIABLE SPEED DRIVEN VANE PUMP Filed Feb. 5, 1949 s Sheets-Sheet 1 IN V EN TOR.

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June 17, 1952 H. c. FRENCH 2,600,633

CONSTANT VOLUME VARIABLE SPEED DRIVEN VANE PUMP Filed Feb. 5, 1949 :5 Sheets-Sheet 2 I I "I I I 56 Inn: H II H 58 HIM .59

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INVENTOR. 74 M BY k m/z H. C. FRENCH June 17, 1952 CONSTANT VOLUME VARIABLE SPEED DRIVEN VANE PUMP 3 Sheets-Sheet 5 Filed Feb. 5, 1949 7/ INVENTOR. BY "*7 C M Patented June 17, i952 UNITED STATES asreur OFFICE:

2,600,633; ooNsTAuT'voflUME VARIABLE seem DRIVENI'VANEPUMP Henry 0. Frencl 1, ;E lm- Grove, Wis assignor; to;

The Heil Co Milwaukee, Wis; a corporation of- Wisconsin Application February-5, 1949; Serial No: 7 1,758-- ee ai (01. 103-420) This inv'ention relates-to improvements in icon stant volume variable: speed: driven vane pumps.- vane type pumps; whendriven by: a variable speed engine, arecobjectionable inamumbergoi,

situations because of the fact that; variations in the speedof operationnof the engine will cause the: volume of liquid delivered per unit: of time to vary in accordance with the: speedof the engine; When this :typeof "pump is used inan hydraulic steering system this objectionable feature-is particularly noticeable. The; pump is, of course,

driven. bythe same. engine; which propels the,

vehicle .andimust. be capableof furnishing suitable: hydraulic power. for steering regardless; of the. speed i at which the vehicleiis 1 being -driven,- as: steering-s must be done atuall speeds, It a tractor; is proceeding at very; slow speed the volumezof oil delivered by the pump forgsteering purposes may be entirely insufiicient to cause steering; On the other hand forcertain uses,

a-vane type-of pump, may. deliver too greata volume-of fluid when thegpropelling engine is being driven at a'high speed.

Vaneipumps of; the typewith which the present invention is concerned are, however, generally desirable for use; in hydraulic systems and it is, therefore; avgeneral object of the present inven: tion to, provide a; strnctureof the class-described which; isan; improvement over 1 the; structure shown and: described inmy prior application Serial No. 628A3-5, filed-November- 14 1945 and which provides means;whereby a substantially. constantvolume of hydraulic fluidper'unitpftimesis delivered into the pressure -line regard} less of the, speed of the propelling; engine; or: other prime: mover;

It is a" more specific objectxofthe presentin:

vention'l to providein; a puinpof the; class-'de-r scribed having a rotor formed withfloatingf'vanes and having :aregulating ring: around the-vanes, means whereby thered's a; natural thrustronthe regulating ring due :to oil "pressure-in the pump chamberin a direction toward the plunger tothereby make it unnecessary too-employee heavy spring-to urge:the' 'regiilatirigiring in. this direction; "Thus-during;operationaofethe=pump less power is J-taken' to overcome-:thetension oi the spring and there is less possibility; of overheat,

ing takingplace in the discharge duct,

A iurther object of the'invention isto pro:

videa-structure as above describedwherein thereis I a difierential piston to; cause; the plunger; to normally exert athrust againstathe regulating, ring in a-- direction to coimtractathes' naturalithrust reirred to mthe paragraph-above;

A further object of the invention isatoaprbvide a, pump. wherethere is thrust bearing; means supportingthe regulating ring on one-side; there-s:

of, so that pressures will act' on vthefring-in, ay-rece tilineal direction only;

With the above-and other-1 objects in viewwthe invention consists ofwthe improved vane pump,

and all its; parts and combinations; as setter-thin thezclaims; and all equivalentszthereof;

In the accompanyin raw na; illu trat n one: complete embodiment of the preferred form; or

t e, invention, n which -theasame-ref emenumerals; designate; the; same parts in all of the; views:

Fig. 1; is a longitudinal sectional view through the pump casing taken-approximatelyon thelli-neq Fig;- 2- is a sectional view taken approximately Fig. 3 is a'diagrammatic view inside elevation; showingrthe pumpappliedto thehydraulicisteer ing system-of a vehicle.-

Reierring more particularly to the drawing;

themuneral-S designates a. main casingportio'n;

having-1a cylindricalpumpchamber fi thereinic A;

drive;shaft- 1 extends axiallyOfth chamber- 6A andits ends, are suitably journalled-in opposite ends of the casing-5 asat 8-and-9. One-end [E of the shaft projects-externallypi the -caSing an'd may-be driven by any suitable sourcefsuch as the 0 power takeoff, H froinqthecombustion enginei2 -o f a vehicle I 3 such as 'atraptorg (see 1') Rotatable'with the: shaft- 1 and positioned within- -the; chamber 6-- a rotorrj l having its periphery concentric with the wall of, ther chams ber- 6;

The periphery of the rotor is; formed withangled transversely extending-slots l5-;f or slidabl-yreceiving :vanes i 6,- asis customary in apva-ne; type of pump. o Surroundin :the--;outer-- ends 110i; v nesis a-regulatingrring. l1; the.-internal,:di: v ameter OfWhiOh is substantially:greatenthan:the;

external diameter :of, the, rotor; 14

One I peripheral" portion 0f L-the; regulatingaring; is, contacted, by; a relatively; lightweigh-tween spring 7 [8. 1 The la-tterisaccommodatediinzthe r hollow stem portion l91 ofzaiscrewz anuzthee screw is threaded-through thewallof: thecasing- 5" andhas: an exteriorly accessible:- end zasosthatz the pressure; exerted on the l regulating-rin by; the.:springi l 8 may: be "varied;

Positioned approximately from: the: spring;

I 8'5isa carriage: 2 I having .a concavmsurface-ipmition 2 2 to fit the peripheral portiohoflthe regulate ingiringzasshown-inFig:;2:. The-icarr-iageeismovs able in the directions indicated by the arrows on balls 23 or other anti-friction members. The latter are suitably interposed between the carriage and a supporting block 24. A swingable link 25 which is pivotally associated with both the carriage and block connects the two members. Due to the slotted pivot 26 in the block, rectilineal movement of the carriage on the anti-friction balls 23 is permitted. A suitable cover 2'! surrounds the anti-friction balls and said cover may have side loops 28 through which sides of the link 25 pass. The assemblage of the carriage 2|, antifriction members, and block 24 comprises a thrust bearing assembly. The block 24 is connected by bolts 29 or other suitable means with an externally accessible plate 36, and the latter is detachably connected by bolts 3| with a tubular extension 32 of the casing 6.

Opposite the spring l8, the periphery of the regulating ring is engaged by the inner end 33 of a plunger 34.

Oil drawn into the pump through the suction line 35 enters an end of the chamber 6 through an arcuate port 36. This opening is arranged to direct the oil into the space between the rotor and regulating ring and between the vanes as is customary. On the opposite side of the axis of rotation of the rotor from the intake port 36 is an arcuate discharge port 31 which communicates with an outlet passageway 38 leading through a passageway 39 and through an orifice 64 to a reduced pressure fluid chamber 40. It is important to note that the gaps 4| and 42 between the ends of the arcuate ports 36 and 3! are located off of the center lines of Fig. 2 about 10-15. By this arrangement, the naturalthrust on the regulating ring, due to the oil pressure in the pump chamber, extends in the direction indicated by the arrow 0, which is at right angles to the center line of the gaps 4| and 42, rather than at right angles to the center line Due to the fact that movement toward the left, referring to Fig. 2, is prevented by the carriage 2|, the oil thrust indicated by the arrow is resolved in a rectilineal direction toward the end 33 of the plunger 34. This force, therefore, supplements the force exerted by the spring |8 and eliminates the necessity of using a strong spring.

Connected to a side portion of the casing by bolts 43 is an auxiliary casing 44. The auxiliary casing has a cylindrical pressure chamber 45 one end of which communicates through a bore 46 in the casing 5 with the pump chamber 6. A bore ,41 connects the outer end of the auxiliary casing with the other end of the chamber 45 and the bore 41 is in axial alinement with the bore 46, but is of less diameter.

The plunger 34 has an inner portion of a diameter to fit the bore 46 and has an outer portion of reduced diameter to fit the bore portion 41. Piston rings 48 and 49 are positioned in grooves in the plunger portions to form oil seals while permitting reciprocating movement of the plunger. Carried by an intermediate portion of the plunger and positioned within the chamber 45 is a disc-like piston 56 having a peripheral oil sealing ring 5| seated in a peripheral groove in the usual manner. Due to the difference in the diameters of the plunger portions it is obvious that the inner face 52 of the piston has less area than the outer face 53 to create a differential piston arrangement. The plunger is formed with a longitudinal duct 54 which communicates with the outer end of the plunger and also through transverse ducts 55 at its inner end with the pump chamber 6. These ducts open the chamber for the spring 5'! to the chamber which surrounds the regulating ring I! so that the spring chamber is under a negative pressure the same as the chamber which surrounds the regulating ring H. The latter chamber is under a negative pressure because it is in communication with the line 35 by means of the duct 16 as shown in Fig. 1.

Connected to the outer end of the auxiliary casing portion 44 and projecting therefrom is a cup 56 accommodating a spring 51. The inner end of the spring engages a washer 58 which surrounds a reduced outer end portion 59 of the plunger 34. The spring, therefore, serves to normally urge the plunger inwardly to the position illustrated. The other end of the spring engages a disc 60 and the'disc is acted upon by the inner end of an adjustment screw 6|. A threaded cap 62 normally covers the projecting end of the adjustment screw. It is apparent that manipulation of the screw 6| will vary the tension exerted by the spring 57 on the plunger 34.

The reduced pressure fluid chamber 40 communicates through an annular duct 63 with that side of the piston chamber 45 which is adjacent the large face 53 of the piston. The chamber 40 is also connected by an orifice 64 of a metering valve with the oil passageway 39.

Threaded into the auxiliary casing 44 is a metering screw 65 which projects through the chamber 46 and which has a conical valve end adapted to cooperate with the orifice 64 to adjustably regulate the volume of fiuid delivered per unit of time by the pump into the chamber 40 and out through the outlet line 66 (see Fig. 3).

In use of the pump, the rotor l4 being in operation and the regulating ring being positioned as illustrated in Fig. 2, oil or other hydraulic fluid will be drawn into the pump through the intake port 36 and will be ultimately delivered under pressure into the outlet port 37. During operation the spring 5'! will urge the regulating ring toward the eccentric condition illustrated in Fig. 2 in which there is a maximum delivery from the Where the pump is to be used in a hydraulic steering system H of the vehicle |3 (see Fig. 3) the parts are so proportioned and the spring 51 is so adjusted by the screw 6| that the tension of the spring 51 will resist a pressure up to five hundred pounds per square inch acting toward the spring 51. The pressure referred to is that created by the oil in the pump chamber, which as before explained has a natural tendency to urge the regulating ring toward the plunger 34, plus the pressure exerted by the spring l9, plus the pressure exerted by the oil which flows through the bypass 67 to act on the inner face 52 of the piston 50.

The metering valve screw 65 is set to permit flow into the pressure line 66 of a selected volume per unit of time according to the particular requirements. In the example which follows, the valve is set to permit a flow of all the oil that can be moved when the differential in pressure between the pressure in the passageway 39 and that in the chamber 40 does not exceed three hundred pounds.

Assuming that there is 230 pounds per square inch pressure in the passageway 39 and200 pounds per square inch pressure in the chamber 40 and in the pressure line 66, which differential in pressure is due to the continuous outflow through the line 66, together with the inability of the orifice 64 to allow more than a predetermined amount m pass into the line 66 per unit of time. The

present invention will prevent" this pressure differential from substantially exceeding 30; pounds regardless" of the speed at which the rotor M is pressure of the oil against the other face 53 off the piston. This pressure acting'on thelarge face 53 will be the pressure existing in the pressure line 66. This pressure will permitoutwardmove ment' of the piston only a distance which in direct-proportion to the difference in the pressures between that existing in: the passageway 39 and that-existing in the chamber 40. The net result will be a small movement of the piston outwardly to permit movement of the regulating ring H to a less eccentric position and cause a decrease in the pumping action and a decrease in the volume of oil flowing from the pump through the meter-' ing valve orifice 64. It is thus apparent that the differential piston 50. will act to always maintain a desired pressure differential between the passageway 39' and the pressure line 66-. This will, therefore, result in the delivery'ofa substantially constant volume. by the pump regardless of the speed of the engine I1 which is driving" the rotor 14'.

By having the gaps Al and flibetween theends of the ports 36 and 31 positioned 45 off of the center line l-l of Fig. 2, as illustrated, there is a natural oil thrust existing in the space betweenthe rotor l4 and regulating ring ll tending to aid' the spring, 18 in moving theregulatingring' toward the plunger 34 and against the tension of the spring 51. This natural thrust is due to the fact that there is a greater percentage of the length of the outlet duct 31 toward the plunger 34 so that the discharge pressure of the oil is resolved in a direction to act toward the plunger. Thus a light spring l8 may be used with theresult that when the pump is operatinglnormally, less power is taken to overcome the tension of thespring 18; Also there is less tendency for overheating in the discharge duct. I I V In addition, by having the difierential faces on the piston 50, the plunger 34 can exert a thrust against the regulating ring to counteract the thrust caused by the off-center position of the ports 36 and 31; Thus a balance is obtained on the two sides of the piston making a very sensitive arrangement.

By means of the thrust bearing carriage 2|, the ring is so supported on-one side as to cause all movement due to natural oil thrust to be resolved in a rectilineal direction toward the plunger Various changes and modifications may be made without departingfrom the spiritot the invention, and all of such changes are contemplated-as may come within the scope ofthe claims.

I claim:

1. In a vane pump having a rotor provided with inwardly directed peripheral recesses, having a freely rotatable, floating regulating ring normally eccentrioally surrounding said rotor, having fluid impelling members movable inwardly and outwardly in'saidrotor' recesses with their outer endsengageable with the inner-periphery oftheregulating ring, andhaving acasing provided with a pump chamber, there being inlet andoutlet-ports peripheral portion. of said regulating ring, said plunger having differential piston mechanism associated therewith responsiveto changes in the pressure diiferential between the duct portions on the two sides of said metering orifice, and a; thrust bearing having a concavepart shaped to, fit and engageablewith a peripheral portion or said ring which is opposite said inlet port, said; thrust bearing including a carriage mounted for movement in a direction parallel to the; axisj or said plunger, the inlet and outlet ports being so located with. respect to the axis of said plunger that the discharge pressure of oil in the pump chamber exerts a natural thrust on the regulat ing ring in a direction to cause movement of the ring and thrust bearing carriage toward" the plunger.

2, In a .vane pump havinga rotor provided with, inwardly directed peripheral recesses, having. a floating, regulating ring normally eccentrically surrounding, said rotor, having fluid impelling; members movable inwardly and outwardly in said rotor recesses with their outer ends engageable with the inner periphery of the regulatingring, and having a casing provided-with apumpcham her, there being an arcuate. inlet. port, in anend of said pump chamber extending for less, thanv and there being an arcuate discharge port, in said end of the pump chamber also, extending for. less than 180 and of substantially the same length as said inlet port, there being a gap between one pair of. adjacent ends of said arcu'atel ports and there being. a. diametrically oppositely disposed gap between the other ends of said ports.

said pump having a discharge duct leading from said discharge port and there being a metering. orifice of restricted size interposed in said dis.- charge duct, means for driving said pump at variable speeds, and controlmeans for said IBQU': lating'ring including a plunger movably engageable with a peripheral portion of said regulating. ring, said plunger having diiferential' piston;- mechanism associated therewith responsive to, changes in the pressure differential between the, duct portions on the two sides of said meterin orifice, said gaps between the. ends: of. the inlet: and outlet ports being so located out of alinement. with the axis of said plunger that the discharge pressure of oil in the: pump chamber exerts a natural thrust in a predetermined direction, and means-for directing movement of the regulatingring-wh'i'ch is in response to said thrust toward the manger,

3'. In a vane pump having a rotor provided with inwardly directed peripheral recesses, having a floating regulating ring normallyeccentricallysurrounding said rotor, having fluid impellingmembers movable inwardly and outwardly in said rotor recesses with their outer ends engageable with the inner periphery of the regulating ring, and having a casing provided with a pump chamber, there being an arcuate inlet port in an end of said pump chamber extending for less than 180, and there being an arcuate discharge port in said end of the pump chamber also extending for less than 180 and of substantially the same length as said inlet port, there being a gap between one pair of adjacent ends of said arcuate ports and there being a diametrically oppositely disposed gap between the other ends of said ports, said pump having a discharge duct leading from said discharge port and there being a metering orifice of restricted size interposed in said discharge duct, means for driving said pump at variable speeds, and control means for said regulating ring including a plunger movably engageable with a peripheral portion of said regulating ring, said plunger having differential piston mechanism associated therewith responsive to changes in the pressure differential between the duct portions on the two sides of said metering orifice, and gaps between the ends of the inlet and outlet ports being so located out. of alinement with the axis of said plunger that the discharge pressure of oil in the pump chamber exerts a natural thrust in a predetermined direction, a thrust bearing having a carriage engaged by the periphery of said regulating ring, said carriage being mounted for movement in adirection parallel to the axis of said plunger and being positioned to direct movement of the regulating ring which is in response to said thrust, toward the plunger.

4. In a vane pump having a rotor provided with inwardly directed peripheral recesses, having a freely rotatable, floating regulating ring normally eccentrically surrounding said rotor, having fluid impelling members movable inwardly and outwardly in said rotor recesses with their outer ends engageable with the inner periphery of the regulating ring, having a casing provided with a pump chamber, and having a discharge duct leading from said pump chamber, there being a metering orifice of restricted size interposed in said discharge duct, means for driving said pump at variable speeds, means engageable with a peripheral portion of said regulating ring to urge said ring in one radial direction, means engageable with an opposite peripheral portion of said regulating ring to urge the ring in the opposite radial direction and including a differential piston responsive to changes in the pressure differential between the duct portions on the two sides of said metering orifice due to changes in the speed of said driving means for causing said pump to deliver a substantially constant volume of fluid regardless of variations in the driven speed of the pump, and a thrust bearing having a concave part positioned to fit and be engaged by a peripheral portion of the regulating ring which is located intermediate the two regulating ring urging means, said thrust bearing having a rectilineally movable carriage portion in contact with the regulating ring.

5. In a vane pump having a rotor provided with inwardly directed peripheral recesses, having a regulating ring normally eccentrically surrounding said rotor, having fluid impelling members movable inwardly and outwardly in said rotor recesseswith their outer ends engageable with the inner periphery of the regulating ring, having a casing provided with a pump chamber, and having a discharge duct leading from said pump chamber, there being a, metering orifice of restricted size interposed in said discharge duct, means for driving said pump at variable speeds, means including a spring for urging said ring in one radial direction, and means engageable with a peripheral portion of said regulating ring to urge the ring in an opposite radial direction from the direction in which it is urged by said first mentioned means and including a piston having oppositely disposed faces of different area responsive to changes in the pressure differential between the duct portions on the two sides of said metering orifice due to changes in the speed of said driving means for causing said pump to deliver a substantially constant flow of fluid regardless of variations in the driven speed of the pump, there being means on the pump side of said metering orifice affording communication between said discharge duct and the side of the piston chamber adjacent the smaller face of the piston, and there being means on the opposite side of said metering orfice afiording communication between the discharge duct and the side of the piston chamber adjacent the larger face of the piston.

6. In a vane pump, a casing having a pump chamber and having a bore communicating with said pump chamber, a rotor rotatable in said pump chamber, vanes projecting from the periphery of said rotor and mounted for inward and outward movement, a regulating ring surrounding said vanes and having its inner periphery engaged by the outer ends of said vanes, a plunger slidable in said casing and having an inner end engageable with a peripheral portion of the regulating ring, resilient means acting on said plunger to normally urge the regulating ring in one radial direction to a position of maximum eccentricity with respect to said rotor, resilient means urging said regulating ring in the opposite radial direction to the direction in which it is urged by said plunger, a piston on said plunger intermediate the length thereof having oppositely disposed faces of different area, there being a piston chamber in said casing within which said piston is movable, said pump chamber having a discharge duct leading therefrom and including a metering orifice, and there being means on the pump side of said metering orifice afiording communication between' said discharge duct and the side of said piston chamber adjacent the smaller face of the piston, and there being means on the opposite side of said metering orifice affording communication with the side of the piston chamber adjacent the larger face of the piston.

HENRY C. FRENCH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Roth Dec. 30, 1947 

